At some point in the afternoon, the boys wandered onto a pond tucked among the rolling hills of their family's farm in southwest Iowa.

The pond was iced over, but the ice was thin: 3 inches thick near the shore and fragile enough in the middle to be broken by a diver's fist during the search for the boys.

While no one saw what happened, it appears the boys fell through the ice about 20 yards from shore, officials said.

Family members found the children's belongings near a hole in the ice.

Divers found one of the boys' bodies almost immediately, about a foot under the water right next to the opening. His brother's body was located about 20 minutes later.

Both boys were taken by helicopter to a Des Moines hospital where both were pronounced dead.

The brothers were good students, said John Walsh, the principal at St. Malachy School in Creston, where both boys attended. He said the boys arrived every day to eat breakfast at the school and rode a bus home after classes.

T.J. had just begun playing the trumpet. Nate was learning the saxophone. Their teachers said both were good at reading.

"Nate and T.J. were really great kids. They enjoyed life and they enjoyed sharing their lives with others," Walsh said. "Whenever you saw one, you saw the other. They were close-knit kids."

Grief counselors spent about 30 minutes with both boys' classmates on Monday and were available for students throughout the day, Walsh said. Several children had visited the counselors.

Saturday was unusually warm for the last day of November, hitting 46 degrees, according to the National Weather Service. Cold temperatures earlier in the week and previous weekend had caused ice to form on the pond, officials said.

Because of its unpredictability, basic knowledge of how it forms is very important before investigating a body of water, Klemesrud said. Officials generally recommend not proceeding on any ice less than 4 inches thick.

Ice typically forms thicker on the edges of water and thins toward the middle.

Other factors like snow, water sources and objects sticking out from the water can also affect the quality or thickness of the ice, Klemesrud said.

Officials don't know exactly what prompted the brothers to walk onto the pond. Likely it was just two boys playing, they said.

When the brothers didn't return to their home late Saturday afternoon, their parents, Tom and Leisa Frey, called 911. The call came in around 5:34, and emergency crews from several cities including Prescott, Creston and Corning were on the scene within 8 minutes. Helicopters and a dive team were dispatched immediately.

The Creston Fire Department had ice suits, and firefighters quickly entered the water.

The helicopters took off for Des Moines as soon as the boys were inside and secure, officials said.

The family, which has five other children - three older boys, an older girl and one son in kindergarten - requested privacy Monday.

"It was a loving and supportive family," Walsh said. "They had a good home. Lots of love."